Imaging systems are widely used to capture images of objects. For example, diagnostic images of a person or an animal may be obtained to assist a doctor or other health care professional in making an accurate diagnosis. Another example includes imaging luggage, shipping containers, and/or the like for security and/or industrial inspection applications. Imaging systems often include an energy source and one or more detectors. In particular, energy, for example x-rays, produced by the source travel through the object being imaged and are detected by the detectors. In response thereto, the detectors produce analog electrical signals that represents the sensed energy. The analog data received from the detector(s) is then converted to digital signals for subsequent processing and image reconstruction.
Some imaging systems, such as some computed tomography (CT) imaging systems use direct conversion materials, such as semiconductor materials for the detection of x-rays. For example, these direct conversion materials may operate in a count mode wherein counts are detected based on photons impinging on a detecting surface of the conversion material and absorbed therein that also satisfy certain conditions. For example, x-ray photon energy is converted into electron-hole pairs and the resulting current pulse signals are detected and counted when the pulses satisfy certain conditions. The photon counts received at various locations and views are then used by the system to reconstruct an image of an object. However, in conventional CT detector modules using direct conversion materials, some charge generated by x-rays absorbed within the material can get trapped resulting in less accuracy in the counts from subsequent x-rays. This inaccuracy in counts can adversely affect subsequent image reconstruction using this count information. The problem can be particularly acute at higher count rates where the magnitude of charge generation is larger with the probability of trapping events being proportional to the amount of charge.